The proposed research is designed to gain an understanding of the way in which complex vibrotactile patterns are processed by the skin. The project will examine a number of ways of presenting vibratory patterns to the fingertip using a computer to control the Optacon, a reading aid for the blind. The patterns will be letters of the alphabet. The ability of ss to recognize letters, presented in various ways, will be measured in the presence of masking stimuli. In addition, the ability of ss to read with these vibrotactile patterns will be measured. Sighted ss, who may be particularly good at vibratory pattern recognition tasks, will be tested for their ability to read rapidly through their fingertips. Measurements are planned on masking of letters presented through the Optacon (recognition masking) and masking of relatively simple vibratory signals (detection masking). The effects of changing the intensity of the masking stimulus and the time between the masking stimulus and the test signal on both recognition and detection will be measured. The effect of a number of variables on vibrotactile spatial summation between two loci on the skin will also be measured.